'All Towns' is a Statewide model, whereas 'Similar Towns' is a stratified model by Municipal Reference Groups. In other words, 'Similar Towns' are scored using only a subset of towns with similar social determinant and demographic variables.
Census Block Group
Low and Very Low Birthweight Babies is a measure of the adequacy of fetal growth during pregnancy. It can result from pre-maturity (gestational age less than 37 weeks), intrauterine growth retardation, or other factors. Low birthweight refers infants weighing less than 2,500 grams (about 5.5 pounds) at delivery and very low birthweight to infants less than 1,500 grams (3 lbs. 3 oz.).
Low birthweight is a major cause of infant mortality and long-term health problems, and decreasing birthweights less than 2,500 grams are associated with increasing risk of death within the first year of life. In addition to increased risk of mortality, low and very low birthweight are associated with increased risk of disability, such as mental retardation, cerebral palsy, and vision and hearing disabilities.
Among the risk factors for low birthweight babies are low socioeconomic status, low level of education, nonwhite race, poor nutritional status, use of alcohol and drugs, environment and inadequate prenatal care.
Connecticut Department of Health, Office of Vital Records - Birth Certificate. http://www.ct.gov/dph/cwp/view.asp?a=3132&q=394598